1. Field of the Invention
The present invention relates to a transparent solid detergent composition. More specifically, it relates to an improved transparent solid detergent composition containing an N-long chain acyl acidic amino acid salt.
2. Description of the Related Art
A transparent solid detergent composition gives a feeling of high quality and has a high commercial value, and thus is used for soaps for washing the face and the like.
Usually conventional transparent solid detergent compositions are prepared by using fatty acid soaps as the base, and saccharoids such as glycerol, sorbitol, propylene glycol, or polyols as clarifiers, by the frame kneading method or mechanical kneading method.
The structural clarification mechanism of the transparent solid detergent composition thus prepared is considered to be such that the group of fibrous fine crystals of an opaque solid detergent composition with optically discontinuous sizes to visible light are vertically cleaved primarily relative to the fiber axes, which are made finer to the wavelength of visible light or less, to thereby clarify the solid detergent (Yu Kagaku 18, 804 (1969)).
Nevertheless, the transparent solid detergent composition obtained according to this clarification mechanism does not provide a good transparent appearance, and in the course of usage, a tendency toward a degrading of the commercial product value has been recognized, such that the soap surface is gelled and becomes opaque.
Accordingly, also in the prior art, a transparent solid detergent composition composed mainly of N-long chain acyl acidic amino acid salt has been developed (Japanese Unexamined Patent Publication (Kokai) No. 55-25465), and this transparent solid detergent composition has an excellent transparency, and further, does not have the drawback of becoming opaque during use.
Nevertheless, the above-mentioned transparent solid detergent composition comprising N-long chain acyl acidic amino acid salt has a problem of an inferior useability and a poor high temperature storability.
More specifically, the above-mentioned transparent solid detergent composition has a poor foaming property and does not give a good feeling during use, and is discolored to turn brown during storage under an environment of, for example, 30.degree. C. or higher, resulting in a marked lowering of the commercial product value. Particularly, while displayed on store shelves, it is sometimes left to stand under relatively higher temperatures for a long time, and the commercial product value is greatly affected by whether or not the high temperature storability thereof is good.